Stereodivergent SN2@P Reactions of Borane Oxazaphospholidines: Experimental and Theoretical Studies

摘要: The stereodivergent ring-opening of 2-phenyl oxazaphospholidines with alkyl lithium reagents is reported. N-H derived from both (+)-cis-1-amino-2-indanol and (−)-norephedrine provide inversion products in a highly stereoselective process. In contrast, N-Me yield retention configuration at the P center, as previously reported by Juge co-workers. As result, single amino alcohol auxiliary, enantiomers key P-stereogenic intermediates could be synthesized. Theoretical studies model DFT level have elucidated streochemical course this substrates react step via preferential backside SN2@P substitution phosphorus. N-methylated preferentially two-step frontside SN2@P, yielding ring-opened product which nucleophilic methyl binds to configuration. calculations shown that ...